Inulin clearance

Fig. 6. Solute transport in hemodialysis. Clearance vs solute mol wt for dialy2ers prepared from the two different membranes illustrated in Figure 5. Numbers next to points represent in min /cm calculated from equations 10 and 5. Data is in vitro at 37°C with saline as the perfusion fluid. Lumen flow, dialysate flow, and transmembrane pressure were 200 ml,/min, 500 mL/min, and 13.3 kPa (100 mm Hg) area = 1.6. Inulin clearance of the SPAN...

In another study, the effects of intravenously-injected P840 (600 mgl kg ) and iodixanol (900 mgl kg ) on GFR (evaluated by inulin clearance) were evaluated in anesthetized euvolemic pigs (n = 10). 

Inulin is used in an important test for renal failure called the inulin clearance method (Gretz et al., 1993 Chiu, 1994). As inulin is neither secreted nor reabsorbed in the kidney, it can be administered by injection to measure glomerular filtration rate. The relative amounts of inulin in the plasma and urine give an indication of renal function. 

The following parameters may be determined inulin clearance (GFR), single nephron GFR, fractional delivery of water, sodium and potassium in proximal and distal tubules and in urine. All data are expressed as mean values SEM. Comparison of the effects of compounds to be tested with controls is performed by one way analysis of variance and by Student st-test for paired and unpaired data. 

The clearances of other compounds can be compared with inulin clearances to determine how the kidney functions in the elimination of the test compound. A clearance ratio is constructed by dividing the renal clearance of the test compound (X) by the renal clearance of inulin ... 

Amiloride does not alter renal function (11), but it does block the tubular secretion of creatinine, leading to falsely high measurements of creatinine clearance inulin clearance is not affected similarly (6). 

Serum creatinine and blood urea nitrogen are accepted indicators of renal function in animal model of ischemic AKl, correlating well with GFR as measured by inulin clearance [95]. In the rat and mouse clamp model of ischemic AKl, the serum creatinine and BUN reach a peak in 24-48 hours of reperfusion and normalize by day 6-8 [96]. Thus, this is a reversible model of ischemic AKL... 

A novel technique using 0.75% fluorescein isothiocyanate (FlTC)-inulin to measure inulin clearance in mice has recently been described [98-100]. We have determined that there is an excellent correlation between serum creatinine and inulin clearance in mice with ischemic AKI (unpublished data). We compared serum creatinine and GFR by linear regression and determined there was a highly significant negative correlation between serum creatinine and GFR, with Pearson r = -0.76 (P = 0.004, n = 12)... 

O Donnel P, Burne M, Nemoto T, Keane WF, RabbFI Direct measurement of renal function in mice with ischemia-reperfusion injury comparison of inulin clearance with serum creatinine, (abstract) J Am Soc Nephrol 11 606A, 2001... 

Harvey AM, Malvin RL. Comparison of creatinine and inulin clearances in male and female rats. The American journal of physiology. 1965 Oct 209(4) 849-52. 

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In healthy adults, the value for inulin is in the range of 120-125 ml/day. Since inulin is neither absorbed nor secreted in the tubules, this value corresponds to the inulin clearance. Per day a total filtered volume of 1801 results, which is 60 times the plasma volume or 4 times the total body water. Because only 1-1.51 urine is excreted per day the reabsorption of water is similar to the filtration rate. 

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